how long should we keep our eye makeup?

i know that the cosmetic companies tell us to throw away our mascaras and eye shadows and lipsticks after 3 months of first opening it, regardles of whether it has been consumed or not. but i'm just wondering if, maybe, this is just their way of earning more money and the truth is that make-ups don't expire at all? or is there some truth to the bacteria theory they've been harping about?

no it is not just them trying to make money. make up truly does expire and the "bacteria theory" is no theory its truth. lipsticks however can last a year if properly cared for. eye shadow is ok as long as you change applicators. mascara and eyeliner need to be changed at least every 6 months.

Yes there is truth to the bacteria theory. Make-up does not expire however. If you have never used it you can keep it until which time you do but after use you should only keep it for the tops of 6 months. 3 months is not very long but 6 is the most. You should also never use other peoples mascara because of eye bacteria.

i don't even think of using other people's make-up. that's a totally different thing. what bothers me is the waste. i'm thinking of trying to see what happens if i use my makeup for, let's say, a year?